Aerial extension ladder



Oct. 9, 1923.

R. S. BOLGER AERIAL EXTENSION LADDER Filed Aug. 22. 1921 4 Sheets-Sheet1 m fi c 95 h Gwen way .l pml y Q E Oct. 9 1923. 1,470,139

RQS. BOLGER AERIAL EXTENSION LADDER Filed Aug-- 22. 1921 4 Sheets-Sheet2 gmvewtoz i W 3 ffioe @351 his awe Imago Oct. 9 1923. 1,470,139 R. s.BOLGER AERIAL EXTENSION LADDER Filed Aug. 22. 1921' 4 Sheets-Sheet 5Oct. 9 1923.

A. w t 0 w 7 a. 4 m 1 9 av h s 4 R s BOLGER AERIAL EXTENSION LADDERFiled Aug. 22.1921

\ liii Patented Oct. 9, 1923.

um-ree stares PATENT oFFic ROBERT s. BOLGER, or New Yemen. sssrenor.ro-rnrnaim'rronni. MOTOR 001v:-

VPANY, or New vYonK, n. Y.

AERIAL A CORPORATION. OF DELAWARE. V

z zrnnsron LADDER.

Application filed August 22, 1921. Serial No. 494,130.

Y '0 all whom it may concern:

Be itknownthat l, item-1R1 S. BoLsER, a citizen of the United$ta-tes,residing in the h I l t- 'f tl 't f New coiougii oriian 1a an, 71e 01 y 0 York, in the State of N ew I ork, have invented certain newand useful Improvements in rierial Extension Ladders, of which thefollowing is specification, reference being had to the accompanyingdrawings, forming a part hereof. I e I This invention relates'to aerialextension ladders of a type which. is very wel known,

broadly speaking, and'has for its principal object to improve suchladdersin certain respects, as will appear more particularlyhereinafter. y I p The type of ladder to which the iinprove vments areparticularly applicable is one in which spring plungers serve to raisethe ladder while pull-down cranks are employed to return the ladder toits bed against the action of the springs. In such ladders mechanism isemployed for their traverse present 'iinprovements'have to doprincipally with one or more of the elements enu merated above and seekto bring them into a relationship which is more effective in operationand more convenient for in anipulation bya single attendant.

Reference is now to be had to t panying drawings for detailed d ofasuitahle embodiment of the various iiuproved features, in whichdrawings- Figure 1 is a view in side elevation of the r f improvedladder and controlling mechanism, v Figure 2 is a view in plan thereor,the

bed ladder and its supports beir emoved a L in the interest ofclearness.

Figure8 is a view 1n end elevation ,of much of the construct1onas'illustrated v Figure 1.

I in

Figure l is a fragmentary detail view section through the turn-tabletaken on the plane indicated by the line li of Figure 2 connectionsdescribed.

in I

and looking in the direction ofthe arrows.

Figure 5 is a detail view in vertical section of the controlling wormshaft taken on the plane indicated by the line 55 of Figure 2 andlooking in the direction of the arrows.

' Figure 6 is a view in transverse section through the worm shafttakenon the plane indicated by the line 66 of Figure 2 and looking in thedirection of the arrows.

Figure 7 is a fragmentary-detail view in section on the line 77, Fig. 2of the mechanism for operating the turn-table and the centering locktherefor.

igures 8 and 9 are detail views in horizontal section through theoperating shaft for the turn-table showing the improved lock mechanismassociated therewith and taken on theplanes indicated by the respectivelines 88 and 99 of Figure l and looking in the direction of the arrows.

Figure 10 is a view in side elevation of the hand operated detent forthe centering lock. Thebed ladder a is supportedpivotally at a onA-frames a secured at opposite sides of a rotatable turntable b on whichall the improved mechanism is mounted. The ladder (4 has extendinglongitudinally thereof on its upper and lower sides truss rods, 0, cwhich pass around its ends and are inter connected so that bendingstresses on the ladder are transmitted throughout the length of suchrods. The ladder or has secured thereto at each side a frame (Z which isconnected to'the ladder at opposite sides of the pivot a so that in theelevating of the ladder it is subjected to an elevating thrust and anelevatin )ull. The lower end of the frame (Z (and a similar frame at theopposite side of the ladder) is pivotally connected to a pull rod 65whichis pivoted to a cross head (Z The cross head has connected to itspring-pressed plungers d slidable in horizontal cylinders which aremounted fixedly on the turn-table b. The springs d within the cylinders(5* have their elevating efforts transmitted to the bed ladderby the Thespiingpressed plungers (Z are heldin retracted position by means of alatch D manually operated by means oflevers D D- which co-operate withthe cross head (Z It is necessary, of

course, to regulate the speed with-which the ladder is elevated underthe influence of the by means of a hand lever e;

p s 7 h i 19 y means f a ak band whiehcooperates with a; brake drum 7",secured to a worm shaft f. Operation of the brake is effected manuallyon the turn-table and operatively connected through the element e ,,t0the brake band. The Worm shaft f is journaled rotatably on theturn-table,butisheid against axial movement thereon by means of suitablebearings, one of which is indicated at f9.- Qn-the Worm shaft 7' ismounted a nut 9., w ich, Whenthe brake a: is e a ed, ca travel freelyalongtheworm shaft. The

:nut g is connected atopposite sides through trunnions g with pull rodsg which areconnee-ted te the cross head d--. From this description itwill be evident that the rate of elevating. the ladder under theinfluence of the springs cLFmay be controlled by thehand brakee. which.Will limit the speed of rota.- tion offtheworrn: shaftlf as the nut gtravelse along it.

When the bed ladder a, is. resting in its cradlei on the. vehicle, theturn-table b will be locked; in centered position by means of a; plungerlock it which is carried Q11 the'turni-table and adapted to enter anOpening i in the stationary bed ring 2' on which the turn-table isrotatably mounted through-balls *2' and 2'. The centering lock .lzis'sna'ppedautomatically into the opening 2', when the turn-table iscentered, by means of 5a springv it". vVV-hen.theturn-table1s to betraversed,-howevr, the centering lock must be withdrawn against theaction of the spring h, by means of improved hand-operatedldevices shownmost clearly in Figures Sland 10.. On a stationarypart of the turntable,indicated asa vertical. tube Z0, is. pivoted.,.anfo rk Theotherend ofthis elementis 'forhe'd and engages with a collarh carried byitheplunger lock h. A bifurcated handle 71: engages over the outer end ofthe element is :and; is pivoted thereto. at

: t lie handle 1: is elevated about the pivot of shoulder- ,l i.

theforltk until the arms Z1 ride over the be'found that the. plunger 72,has been entire- -.ly withdrawn from its entering recess e and isvloekedrin elevated position: by engagement of thearms k wwltlltheshoulder k9.

la is rocked about its pivot so as to clear the carried Then in thisrelation it will This relatimr'Will bemaintained until thehandle armsfrom the shoulder Z66. 'Thereupon the spring h will become effective toforce the plunger it into its recess 2'. i

The mechanism for traversing the turntable is comparatively simple.-.The bed ring 2" has cut on its inner periphery an internal spur gear i'The turn-table Z) has journaledtherein a vertical rotatable shaft Z) onthe lower end of which is carried a pin ion Z2 meshed with the internalgear 71 An operating wheel 5 is carried at the upper end of the shaftZ). Rotation of the shaft 5 with its pinion b will serve to rotate thetuna-table to any desired angular position. in order to lock it in anydesired predetermined angular position, simple and improved devices aremounted on the v'ertical column Zc through which the shaft Z) passes.This position lockis made up from a split section of the tube 711wlnchis 61 111 braced by a split ring is adapted to be compresscdbyoperation of a hand operated nut 14: threaded on to a bolt 1b" whichpasses through the free ends of the split nut it. By

tightening the hand operated ring if the spllt nut is Wlll be compressedand bind the tube 7: on the operating shaft b so to prevent furth'errotation thereof. This locks the turn-table in adjusted angularposition.

W it-h the bed ladder a raised it is necessary to depress it either forthe purpose of adjust-ing it against the building or for lowering it toits cradle. Suitable hand operated pull-down mechanism-is provided inthe improved construction. 0n the turn-table is journaled a worm shaftZ, to theends of which may be applied hand cranks Z for convenientactuation of the shaft. I The worn'i formed preferably adjacent to themid-section of the shaft 15 meshes with.

a worm vgear m on. a stub shaft on which is also supported on theturn-table The inner end of. the stub shaft viii," carries one sectionof any suitable form of clutch, shown in the drawings as a simple dogclutch men'iber, in/ In proximity to the stub shaft m is found one endof the worm shaft f on the end of which is feathered the other member iof a dog clutch which,'by means ofa hand lever f i'nay' he slid intoengage ment with the dog clutch member m In this Way the worm shaft fmay be connected operatively and at will to the worm shaft 1. Rotationofthe worm shaft Z, when the the ladder. The irreversible worm connection.between the worm Z andtheworrrr gear 222 insures a positive 'lockingofthe parts in all positions; against angular inoveni ent. Such relation.also permits the nicest degree of the adjustment of the angular positionof the bedwladder a When in the It will be appreciated that "with thefulcrum a of the bed ladder a so near one end, slight movement of thelower end of the ladder is greatly multiplied at the upper end. For thisreason, a distinct improvement is realized by providing for a very finedegree of movement through the worm Z and worm wheel at. When the ladderis thus nicely adjusted to its proper angular position, it will beheldthere positively by reason of the interengaging worm Z and worm wheel:m. When the clutch elements 7, m are disengaged the'worm shaft f will inconvenient reach of a single attendant,

standing thereon. He'-'may, for instance, readily operate the hand wheel6 to traverse the turn-table; he may manipulate both the lockdevices'for centering or for position, through the nut or the handle 7Jhe may control, the rate of elevating through the brake handle 6 and hemay throw in the dog clutch f by means of the lever 7, whenever theladder is to be pulled down or locked in predetermined an gularposition. This organization of parts, by which such convenient centralcontrol is placed under the handof a single attendant, insures quick andeffective manipulation of the ladder operating mechanism. Further, theimprovements in the component elements entering into this organizationare of a substantial and important character in advancing the art. I

What I claim is:

1. In combination with an aerial extension ladder, a' turn-table,control mechanism for i the ladder mounted on the turn-table andcomprising means to traverse the turn-table, means to elevate theladder, means to lock the turntable in centered position, means tolockthe turn-table in predetermined. adjusted angular position, means tocontrol the rate of elevating the ladder, means to lock the ladder inpredeterminedangular position, and hand operated devices for actuat tosaid worm wheel, and means operatively connecting said worm wheel withthe first worm shaft for the purpose of locking the parts againstangular movement.

3. In combination with an aerial extension ladder, means on which theladder is pivotally mounted and pull-down mechanism for said ladderincluding a worm and worm wheel in irreversible relation for the purposeof transmitting a pull-down effort to the ladder while locking the partsagainst relative angular movement.

4. In combination with an aerial extension ladder, means to support itpivotally, pulldown mechanism including a worm shaft, a nut mounted totravel on the worm of said shaft, means connecting the nut with theladder in pull-down relation, an independent worm shaft, pull d'owncranks for actuating the same, a worm wheel in mesh with the worm on thelast named shaft, and a clutch operatively interposed between said wormwheel and the first named worm shaft for operatively connecting anddisconnecting the two.

In an aerial extension ladder, means to support it pivotally, poweroperated devices connected operatively to the ladder for elevating it, aworm shaft, a nut mounted to travel on the shaft, means to connect thenut to the ladder and a brake operatively associated with said wormshaft to control the rate of elevating the ladder.

6. In an aerial extension ladder, a sup porting bed plate therefor, aturn-table mounted rotatably on the bed plate, a springpressed positionlock carried with the turntable and adapted to engage the plate to holdthe turn-table in centered position, a bracket on the turntable throughwhich the lock passes and a bifurcated handle engaging the lock andhaving a toe co-operating with the bracket to hold the lock in releasedposition against the action of its spring.

In an aerial extension ladder, asupporting bed, a turn-table rotatablethereon, a centering lock comprising a vertical plunger carried on theturn-table and adapted to engage the supporting bed and hand operateddevicesto release the plunger including a pivoted fork ra bifurcatedhandle pi oted to the fork and engaged with the plunger and a toecarried with the bifurcated handle and co-operating with a fixedshoulder carried with the turn-table.

This specification signed this 16th day of August, A. D. 1921.

ROBERT s. 'BOLGER.

